Electric switch operating structure



Original Filed March 21, 1945 June 4, 1957 RUSSELL 2,794,882

ELECTRIC SWITCH OPERATING STRUCTURE 2 Sheets-Sheet 1 9 7a 5 5 r" c l 1| l-- I [lily-i l9 6d J 1 1 IH J 5 l 'J I I-QLI H 'l 50 r I 1 June 4, 1957 F. J. RUSSELL 2,794,882

ELECTRIC SWITCH OPERATING STRUCTURE Original Filed March 21, 1945 2 Sheets-Sheet 2 g ms 45 75? a 5 745 I2, 55

5 b9 7 70 5 "g/ 59 2 7/ z? 65 United States Patent ELECTRIC SWITCH OPERATING .STRUCI Frank J. Russell, Wauwatosa, Wis, assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware 3 Claims. (Cl. 200-104) 202,341, Decem- This invention relates generally to electric switches and is particularly applicable to solenoid operated switches which are capable of general use and are especially adapted for aircraft control. i Q I In the design of electromagnetically actuated switches which are intended for use on aircraft, it has been found that certain characteristics must be provided, which characteristics are briefly summarized as follows: 1) Small size and low weight in proportion to current handling capacity; (2) Ability to withstand severevibrationan'd large accelerating forces; (3) Ability to operate properly under a wide range of temperature, humidity or pressure conditions; (4) Completely enclosed to exclude dust from the contacts and operating mechanism; (5) Ability to operate properly under emergency load conditions; and (6) Confinement and quick extinguishment of arcs.

This application is a continuation arm application, Serial No. 202,341, filed December 22, 19,50; which ap plication, Serial No. 202,341, now abandoned, was a division of my original application which resulted in Patent No. 2,561,450, dated July 24, 1951, for'Electric Switches. Said Patent No. 2,561,450 is assigned to the assignee of this application.

Accordingly, the present invention has among its objects the provision of a simple, rugged and inexpensive solenoid operating mechanism for a switch having the above-noted characteristics.

Another object is to provide an improved solenoid operating mechanism for switches of the aforesaid type which is positive and reliable in operation and which provides for closure of the contacts without rebound.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of the invention which will now be described, it being understood that various modifications may be made in the embodiment illustrated without departing from the spirit and scope of the appended claims.

In the drawings,

Figure 1 is a side elevational bodying the invention;

Fig. 2 is an end elevational view of the contactor shown in Fig. 1;

Fig. 3 is a sectional view on line 33 of Fig. 2;

Fig. 4 is a diagrammatic view of the solenoid operating winding shown in Fig. 3 and control therefor including switch shown in Figs. 2 and 3;

Fig. 5 is a sectional view on line 5-5 of Fig. 3; and

Fig. 6 is a perspective view of the pivoted switch operating lever shown in Fig. 3.

The contactor illustrated in the drawings consists of an operating assembly 1 and a contact assembly 2, the latter of which assemblies is described in detail in my aforementioned copending application. Operating assembly 1 includes a solenoid winding 3 and an associated magnetic plunger 4 which are carried by a pair of end supporting brackets 5 and 6 (Figs. 1 and 2). Contact view of a contactor emassembly 2 includes a plurality of movable bridging Contacts 7 each of which cooperates with a pair of stationary contacts 8 and 8 The stationary contacts 8 and 8 are mounted upon an insulating base'9 which is secured to the end brackets 5 and 6, and the movable bridging contacts 7 are carried by an elongated insulating bar or carrier 10 which is operatively connected to plunger 4 by a pivoted operating lever 11. Base plate 9 has a removable insulating cover 12 mounted thereon and is provided with barrier projections which engage bar 10 and fit into recesses formed on the interior of said cover to provide individual arcing chambers for each of the stationary contacts 8 and 8 More specifically, solenoid winding 3 is mounted within a magnetic casing 13 of tubular form, and, as shown in Fig. 3, is wound upon a bobbin comprising a cylindrical brass tube 14 having a magnetic washer 15 fixed to the left-hand end thereof and a non-magnetic washer 16 fixed to the right-hand end thereof. Washer 15 is secured between a shoulder 17 and an inwardly extending flange projection 18 formed on the left-hand end of casing 13 and washer 16 fits snugly within the right-hand end of said casing. Brackets 5 and 6 are clamped against opposite ends of casing 13 by four bolts 19 to 19 which extend between said brackets. These brackets are formed of magnetic sheet material and each is provided with a rectangular body portion a' having parallel leg extensions b and 0 formed on opposite sides thereof. The body portions a of brackets 5 and 6 are provided with corner openings (Fig. 2)' for receiving the bolts 19* to 19 and said brackets" are so'a'ri'anged that the leg extensions b and c thereof extend outwardly with respect to casing 13. Washer 15 is shouldered to fit within an opening 20 in the body portion a'of bracket 5 and the left-hand face thereof is shaped to provide an annular pole projection 21,'as shown in Fig. 3. A core plug 22, secured within an opening in the body portion 6 of bracket 6, extends into'the right-hand end of sleeve 14.

Plunger 4 is slidably supported within sleeve 14, and as shown in Fig. 3 the opposing faces of plunger 4 and core plug 22 are provided with drilled openings for receiving a coiled spring 23. Upon energization of solenoid winding 3, plunger 4 is attracted against the action of spring 23 into engagement with core plug 22. Plunger 4 is also provided with a magnetic ring projection 24 which seals with the face of the pole projection 21 on washer 15 at the same time that the inner end of said plunger seals with core plug 22. The outer end of plunger 4 is provided with a grooved extension 25 for re ceiving operating lever 11.

As shown in Fig. 6, operating lever 11 comprises two sheet metal stampings secured together by spot welding and formed to provide a bifurcated end portion 26 which fits snugly within the grooved extension 25 on plunger 4. Said operating lever is also proyided with a pivot pin 27 Which'is located midway between the ends thereof and as'showii in Fig. 3 leg extension of bracket 5 is slotted to receive said' lever-and is provided with indented bearing portions 28 on opposite side of said slot for receiving said pivot pin. i

As shown in Figs. 3 and 5, the contact carrier 10 is rectangular in shape and ornprises two molded insulating sections 10 ai1d'10 which are secured together at opposite ends by rivets 42."'These sections are formed to provide equally spaced openings 43 for receiving the bridging contacts 7, and as shown in Fig. 5 each of said bridging contacts is yieldingly supported and held in assembled position upon carrier 10 by a pin 44 and an associated spring 45. The opposing faces of insulating sections 10 and 10}? are recessed to receive the pins 44 and springs 45 associated with bridging contacts 7, and

said faces are also recessed to provide a slot 46 for receiving the upper end of operating lever 11.

For effecting movement of the bar 10 in a straight line parallel to the line of movement of the solenoid plunger 4, the bar 10 is guided and supported within an elongated recess 47 formed in the upper face of base plate 9. As best shown in Fig. 3, the bar or carrier 10 is normally held in engagement with a shoulder 48 on the right-hand end of recess 47 and upon movement of plunger 4 into its attracted position said bar is moved toward the left through the medium of lever ll to effect engagement of bridging contacts 7 with their cooperating stationary contacts 8 and 8 Upon full movement of bar 10 into its extreme left-hand position, bridging contacts 7 are yieldingly held in engagement with their cooperating stationary contacts under the action of their associated springs 45.

Further describing the plunger, lever and bridging contactor carrier assembly, the plunger 4 and'bar 10 are so designed that the same are of equal weight. By this it is meant that the combined weight of the plunger 4, the sealing ring projection 25, etc., is equal to or substantially equal to the combined weight of the bar 10 and its associated contacts 7 and springs 45. Thus, since the lever 11 is pivoted at its midpoint and both the plunger and bar are positioned for movement along parallel lines, it will be seen that any external shocks or forces applied to the contactor switch are neutralized through the medium of the operating lever. It will also be apparent that without the addition of parts and merely by the particular design and arrangement of those parts which are essential to the switch there has been provided an electromagnetically operated switch which is highly resistant to external forces such as the accelerating forces experienced in an airplane.

Associated with plunger 4 is an auxiliary switch 30 (Fig. 4), and, as shown in Figs. 2 and 3, this switch comprises a stationary contact 31 and a cooperating movable spring contact finger 32, both of which are mounted upon an insulating plate 33. Plate 33 is arranged between the leg projections 6 and 6 of bracket 6 and is mounted upon two of the securing bolts 19 and 19 which extend beyond the body portion 6 of said bracket. Contact finger 32 is biased to normally engage stationary contact 31 and has an insulating operating pin 34 associated therewith which is slidably supported within a central opening in core plug 22. An enlarged head 35 formed on the inner end of the pin 34 is held in engagement with plunger 4 under the action of spring 23 to provide for movement of said pin with said plunger.

As shown in Fig. 4, solenoid winding 3 is adapted to be connected across a direct current supply circuit illustrated by lines L L by a pilot switch PS. Also, as illustrated in this figure, solenoid winding 3 is provided with coil sections 3 and 3 the latter section being normally shunted by auxiliary switch 30. Thus upon closure of pilot switch PS, coil section 3 is energized to effect movement of plunger 4 toward its attracted position. However, prior to full movement of plunger 4 into its attracted position insulating pin 34 engages spring contact 32 to move the same into open position for connection of coil section 3 in series with coil section 3. The current in coil section 3 is reduced upon inclusion of coil section 3* but when plunger 4 moves into its attracted position coil section 3 acts cumulatively with coil section 3'. Also upon movement of plunger 4 into its attracted position, the holding force thereon is augmented by sealing of ring projection 24 with the face of pole projection 21 on washer 15.

End bracket is provided with a molded insulating cover member 5 which forms a closed chamber 38 for the front end of plunger 4, and end bracket 6 is provided with a similar cover member 6 which forms a closed chamber 39 for auxiliary switch 30. Each of these cover members 5 and 6 fits tightly between the leg projections a and b of its respectively associated bracket 5 and 6 and is U-shaped to engage the body portion a thereof on opposite sides. Also each of these cover members is rendered dust-tight by means of strip felt edgings 40 (Fig. 3). As shown in Figs. 1 and 3, the bolts 19 and 19 are used to secure'cover member 5 to its associated bracket 5 and the bolts 19 and 19 are used to secure cover member 6 to its associated bracket 6.

It has been found that the above described solenoid operating mechanism effects closure of bridging contacts 7 without substantial rebound, and also provides an exceedingly large operating force for moving said contacts into circuit closing position and for maintaining the same closed. It thus becomes apparent that the described switch operating structure embodies the desirable characteristics aforementioned.

Another desirable feature of the subject switch operating structure is that provision is made for easy adjustment of the contact assembly 2 with respect to the operating assembly 1 in order to vary the degree of movement of the carrier 10 upon movement of the solenoid plunger into its attracted position. As hereinbefore described, base 9 is secured to brackets 5 and 6 by screws 41. These screws extend through slotted openings in legs 5 and 6 of brackets 5 and 6 and are threaded into base 9. Thus by loosening screws 41 base 9 can be adjusted with respect to brackets 5 and 6 to vary the degree of movement of bar 10 upon energization of solenoid winding 3. As is apparent from Fig. 3, upon adjustment of base 9 toward the right, plunger 4 is moved outwardlywith respect to winding 3 to increase the degree of movement of bar 10, while adjustment of said base in an opposite direction has an opposite effect. Base 9 is adjusted with respect to brackets 5 and 6 by a pair of set screws 69. These set screws engage shoulders 70 formed on opposite ends of base 9 and are carried by brackets 71 fixed to the legs 5 and 6 of brackets 5 and 6.

I claim:

1. In a circuit controller, in combination, an operating assembly including a solenoid winding and a single rectilinearly movable plunger having telescopic relationship thereto and attractable thereby, a single coiled compression spring interposed between one end portion of said plunger and an abutment member to oppose such attraction, a multiple contact assembly mounted upon said operating assembly and including a circuit controlling element movable between given circuit controlling positions in a straight line parallel to the line of movement of said plunger, a pivoted operating lever connecting said plunger to said circuit controlling element, said plunger and said circuit controlling element being of equal weight and said operating lever being pivoted at a balancing point midway between said plunger and said circuit controlling element to prevent movement of said circuit controlling element under the action of accelerating forces caused by shock, and a normally closed auxiliary switch for shunting a portion of said solenoid winding, said auxiliary switch being associated with said plunger to provide for opening thereof during final movement only of such plunger into its attracted position to thereby increase the effect of said winding on said plunger when the latter is ifsuch attracted position as compared with the effect thereon during substantially the entire movement of said plunger to its attracted position.

2. An operating structure for a completely enclosed, dust-tight electric switch comprising, in combination, a rectilinearly movable contactor carrier, a solenoid plunger positioned for rectilinear movement parallel to said contactor carrier, said plunger having an associated stationary winding for effecting movement thereof, a centrally pivoted operating lever the opposite ends of which are connected to said carrier and said plunger, respectively,

, said carrier and said plunger being of substantially equal weight whereby movement of either said carrier or said plunger by external forces is resisted by the counterbalancing force of the other, and a normally closed auxiliary switch normally shunting a portion of said stationary winding, said auxiliary switch being operable by said plunger to provide for opening thereof during final movement only of said plunger into attracted position to thereby increase the attractive effect of said winding on said plunger.

3. An operating structure for a completely enclosed, dust-tight electric switch comprising, in combination, a rectilinearly movable contactor carrier, a solenoid plunger positioned for rectilinear movement parallel to said contactor carrier, said plunger having an associated stationary winding for effecting movement thereof, a centrally pivoted operating lever the opposite ends of which are connected to said carrier and said plunger, respectively, said carrier and said plunger being of substantially equal weight whereby movement of either said carrier or said plunger by external forces is resisted by the counterbalancing force of the other, and-a normally closed auxiliary switch normally shunting a portion of said stationary winding, said auxiliary switch being operable by said plunger to provide for opening thereof during final movement only of said plunger into attracted position to thereby increase the attractive efl ect of said winding on said plunger, said first mentioned switch and said auxiliary switch being rendered inherently shock-proof by continuously balancing the weight of said movable carrier against the weight of said plunger.

References Cited in the file of this patent UNITED STATES PATENTS 570,212 Wurts Oct. 27, 1896 599,344 Murphy Feb. 22, 1898 1,207,016 Fryer Dec. 5, 1916 2,049,747 Parsons Aug. 4, 1936 2,086,628 Matejka July 13, 1937 2,266,536 Cooper Dec. 16, 1941 2,390,344 Ayers et al. Dec. 4, 1945 2,475,331 Lowndes July 5, 1949 FOREIGN PATENTS 227,014 Switzerland May 15, 1943 

